Telephone subset arrangement



March 25, 1941.

E. s. McLARN 2,23(i,105v

TELEPHONE SUBSET ARRANGEMENT Filed Oct. 29, 1938 3 Sheets-Sheet 1 ERNEST MLA/7N ATTORNEY March 25, 1941. E, s McLARN 2,236,105

TELEPHONE SUBSET ARRANGEMENT Filed OC'I.. 29, 1938 Y3 Sheets-Sheet 2 INVENTOR ERNEST MMA/PN ATTORNEY March 25, 1941. E. s. McLARN 2,236,105

TELEPHONE SUBSET ARRANGEMENT Filed 001;. 29! 1938 3 Sheets-Sheet 5 ,Q Sf- ,E

BY F

ATTORNEY Patented Mar. 25, 1941 UNITED STATES PATENT OFFICE TELEPHONE SUBSET ARRAN GEDIEN T Application October 29, 1938, Serial No. 237,697

7 Claims.

My invention relates to telephone apparatus and more particularly .to magneto hand generators for suitable mormting in telephone subscribers sets.

In the magneto telephone subsets now generally in use, the telephone is usually made quite large for the accommodation of the magneto and is generally of radically different design from telephones utilizing local or connnon battery for l ringing instead of the magnetos. Because of these limitations magneto telephone subsets have been very different in appearance from the commonly used manual and dial telephone subsets operation on batteries. Furthermore, this radical difference in structure makes necessary a removal of the telephone instrument and replacing by a difierent instrument if a system is to be changed from a magneto operated to a battery controlled arrangement. Moreover, the difierence in structure yalso results in an increase in the manufacturing cost, since various types of telephone subsets which ldiffered from each other in substantially every respect, were necessary .to supply the `instruments for both types of systems.

Accord-ing to my invention I provide a magneto hand generator, which may be made quite compact in size and so may be incorporated in the usual type of battery .telephone subset. Furthermore, the hand generator in accordance with my invention may be made of such appearance as to render the subset in which it is inserted very similar in appearance to the ordinary 'bat- 3, tery operated telephone.

Another feature of my invention resides in the construction of a hand generator composed of a small number of parts which are mounted so as to be readily acceptable for service or repair with a minimum amount of effort.

Funtherrnore, in accordance with a feature of my invention, the generator is so designed as to be easily started because of the position of the armature with respect to the pole pieces. Also the magneto winding and the armature are made stationary so that no sliding connection is required between the generator and the line. Because of the stationary armature and rotatable iield it is possible to build the magneto generator of smaller size. The .permanent magnet field pieces may be made in semi-circular shape and mounted about said armature so as to provide a ywheel efiect upon rotation.

Another feature of my invention includes a hand generator in :a telephone subset in which the gearing for driving the generator is mounted outside vthe regular telephone casing.

With these features in view it is 4a principal object of my invention to provide a magneto generator of compact size.

It is a further object of my invention to provide a generator :of suitable shape to conserve space lan-d to permit the design of a magneto telephone of small and pleasing contour.

It is .a further object of my invention lto pro- 10 vide a hand generator which easy to start.

It is a still further object of my invention to provide a hand generator in which the field lis made rotatable and the armature is stationary, thus eliminating pivotal frictional points for l5 .carrying out the winding terminals.

It is a still further object of my invention to provide fa hand generator made of a small nurnber of parts which can be readily and cheaply manufactured and assembled. 20

It is a. still further object of my invention to provide a telephone subset using a signaling means such ,as my improved hand generator in which the pants may be made readily accessible for servicing the telephone subset.

Fur-ther objects and advantage of my invention may be gathered from a reading of the particular description of my invention, with reference to the accompanying drawings in which Fig. 1 illustrates a cross-sectional View of a 30 wall .type telephone constructed in accordance with my invention,

Fig. 2 illustrates a cross-sectional View taken along the line 2--2 of Fig. l,

Fig. 3 is another sectional View of .the hand generator made along .the line 3-3, of Fig. l,

Fig, 4 is a sectional view along the line 4-4 of Fig. 3,

Fig. 5 is a plan View of the generator taken aiong the line 5 5, of Fig. 3,

Figs. 6 and 6A are details of parts of the generator, and

Fig. 7 is a Wiring diagram of a subset illustrating the related parts of a generator and the telephone subset circuit.

Turning now more particularly to the drawings, Fig. 1 illustrates a suitable form of wall telephone in which base plate lill) is provided upon which :the telephone apparatus itself is mounted. A suitable cover plate |02 is provided .to cover the working parts of the telephone. By removal of this cover plate |02, the interior of the telephone may be readily accessible for suitable repairs. Within the telephone casing is provided a hand magneto generator or other suitable signalling device mounted on a bracket |93. This bracket is pivoted alt point lili to a supporting post IUI fastened to plate f| EB so that the entire signalling unit may be tipped outwardly .for making repairs on the interior surface of the generator, vfor example fthe switch assembly, lor on .the bell circuit without disassembling the enti-re telephone arrangement. `The bracket i||i3 is further provided with projecting legs |05 which may be fastened b-y suitable means :to the upstanding portion lili of base plate |00. The arms |05 may be made of suitable spring material so that the generator unit will be held in place by frictional engagement. However, since there a considerable strain on the mechanism due to the weight and rotation of ,the generator, it is preferable for these parts to be fastened by suitable means such as screws.

The magneto unit itself comp-rises a dished cover plate |97, extending outside the suibset cover plate H32, upon which a suitable crank handle Iii may be provided for operating the generator. On the under sid'e of the plate or cover ili'! and fastened thereto and preferably welded integral with it, is provided a ring gear Hi! (Fig. 2). This gear engages an idler gear I rotatably mounted on an end of a stud shaft i2 secured to the armature I I3 of the magneto. This armature is secured to bracket |03 by suitable fastening means so as to be held fixed with respect to the telephone framework.

The idler gear III meshes with a pinion gear |2|| movably secured to a rotatable hollovi7 shaft member |2| so as to permit a small amount of relative rotation there-between. This member |2| rotates inside a sleeve portion |85 formed on bracket |03 and is secured by suitable means to a cup-shaped pole supporting plate IM. This connection may suitably be made by making the lower end of |2| of square or other non-circular shape so that plate ||i| will rotate therewith. Within the hollow of shaft |2| is slidably mounted a pin |38 provided at one endwith an enlarged head portion ISI, Fig. 3, .and at the other with an insulated contact controlling member |32. Projecting from the enlarged head portion |3| is provided a pin |33. The pinion gear, Fig. 6A, is provided with a portion |23 integral therewith upon which are provided cam surfaces |22 for cooperation with pin |33. The gear |28 is also provided with diametrically offset projections |26 (Fig. 6A) which cooperate with the diametrically disposed recesses |24 in the flange |25 of shaft |2|, Fig. 6, to permit a limited relative or free rotation of gear |20 with respect to shaft |2|. The construction of the shaft |2| and gear arrangement may be clearly seen in Figs. 6 and 6A.

Through the end of pin |30 at a point adjacent the insulated end |32, is provided a laterally projecting pin arrangement |32 which is adapted to cooperate with raised projections |40 provided on the rotor-supporting cover MI. The purpose of pin |34 is to prevent the rotation of pin |3i| until the camming action of pinion gear |25 has driven pin Hit downwardly and shifted the spring contacts. Pin |33 does not turn during the period of free rotation of pinion |20 because it is held by pin |315 which is held stationary by lugs |40 because of the static inertia of the rotor. The rotor does not move until projections |26 strike the projecting surfaces of flanges |25, Figs. 6 and 6A. The rotor comprises the two semi-circular field magnets |132, |63-, the shape of which may be readily seen with reference to Fig. 4. The generator design is such that in the normal or rest position the intersections of the rotor pole pieces |42, I d3, will always be almost exactly opposite the center of the heads of the armature I i2, of the magneto as shown in Fig. 4. These rotor elements are supported in the cup-shaped rotary supporting element ld! Cooperating with the insulated end of pin |35 isthe central contact element |5|l. In its normal position'this contact |50 is closed against its right-hand contact II by which the ringer of the subset is normally maintained connected with the line 50, 55' (Fig. 7). Upon rotation of the generator, however, the contact element |50 is forced to the left opening Contact |5| and closing a Contact at |52 which serves to disconnect the local ringer from the line to connect the generator armature thereto. These contacts are supported in a. suitable insulating arrangement indicated at |53 and supported by a suitable bracket |55 on the supporting bracket The operation of the generator is as follows: Upon rotating part |51 by handle lii, ring gear turns idler gear I I which in turn drives pinion gear |29 at a rate determined by the gear ratio Ibetween the ring gear and the pinion. After turning a short distance projectionsy |25 contact flange |25 and cause rotor MI to turn at the same rate. During the period of independent rotation of pinion gear |213, the cam surface |22 encounters projecting pin |33 on pin |39 forcing vpin |39 downward and causing the insulated end |32 of pin |35 to move contact element |50 from contact |5| to contact |52. Rotor |Li| carries with it the peranent magnets ||2 and M3. These rotating poles create a change in magnetic ux in the armature ||2 causing ilux variations actuating at a rate determined by the speed of rotation of the rotor with respect to the armature and the number of field poles. This variation in magnetic flux in armature ||2 induces a current in the armature winding ||5 connected to the line 5t, 5t at contact |52 and thus causes the alternating current to be transmitted over the line. 59 to the distant sending station.

The conventional magneto hand generator is constructed with horse shoe magnets arranged side by side with the armature revolving between soft iron pole pieces attached to the poles of the permanent magnets. In such construction, the armature will stop either with the heads bridging the air gap and the lines of force concentrated at the edges, or at a position of 9 from this position with the heads contiguous: to the pole pieces and with the lines of force spread over a considerable area. In the former position starting is difficult because of the keeper effect of the bridging armature heads whereas in the latter position, the armature heads are relatively free to move. Inmy generator, the bridging position is entirely eliminated thus eliminating the more diflicult of the two startingpositions. Upon stopping the rotation, pin |353 is returned to its normal position by the spring action of switch member |50, causing pinion gear |2ii to return to a central position with respect to pin projection |33. This may be readily accomplished by the proper choice of value of spring switch member |50.

It is readily apparent that the magneto generator in accordance with my invention is very compact and is of suitable shape to be readily incorporated in the position normally occupied by the calling dial in an automatic telephone arrangement.

While I have illustrated herein a specic structure embodying the preferred form of my invention it should be distinctly understood that this is merely incorporated by way of illustration and is not to be considered as a limitation on the scope thereof. It is evident that varying forms and shapes of the` magneto generator in accordance with my invention may be desired Without departure from the general scope of my invention. What I consider my invention and upon which I desire to secure protection is defined in the appended claims.

I claim:

1. A telephone subset comprising, a supporting plate, a casing having an aperture, a supporting bracket carried by said plate, a magneto generator pivotally supported by said bracket within said casing but spaced from said plate, another subset circuit component supported from said plate between said plate and said generator, driving means for said generator extending through said aperture, and means for removably securing saidgenerator to said supporting plate to prevent pivotal movement of said magneto with respect to said bracket.

2. A telephone signal generator comprising, a rotary cover having internal gear teeth, a gear train mounted inside said cover and meshing with said gear teeth, a shaft operatively associated with said gear train for rotation responsive to rotation of said cover, permanent magnet eld pieces operatively associated with shaft for rotation therewith, and an armature having a winding thereon xedly mounted in the magnetic field of said eld pieces whereby operation of said gear-driving means will induce an electromotive force in said armature windings, said cover being dimensioned to extend through a conventional dial aperture of standard size so that said generator may be mounted in a telephone subset having a conventional dial aperture with said cover and gear train at least partially outside the subset.

3. A telephone magneto generator comprising a frame, an armature carrying a winding flxedly secured to said frame, magnetic field producing means comprising permanent magnets rotatably mounted on said frame for rotation about said armature, means for rotating said ield producing means comprising a shaft operatively connected with said pole pieces, a pinion gear mounted on said shaft and rotatable a predetermined amount with respect thereto, rotatable gear means for driving said pinion gear, a switch normally maintaining said armature winding open circuited, and means operative in response to rotation of said pinion gear for closing and maintaining closed for the duration of such rotation a. circuit for said armature winding comprising a cam portion rotatable with said pinion gear and a follower rotatably xed to said magnetic eld producing means and operated by said cam portion, said switch being operated by said follower and spring tensioned to return said follower and cam portion to a normal predetermined position,

4. A telephone signal generator comprising, a rotary cover having internal gear teeth, a gear train mounted inside said cover and meshing with said gear teeth, a shaft coaXially arranged with respect to said cover operatively associated with said gear train for rotation responsive to rotation of said cover, magnetic field pieces operatively associated with said shaft for rotation thereby, and an armature having a winding thereon xedly mounted in the magnetic leld of said eld pieces whereby operation of said geardriving means will induce an electromotive force in said armature windings, said cover being dimensioned to extend through a conventional dial aperture of standard size so that said generator may be mounted in a telephone subset having a conventional dial .aperture with said cover and gear train at least partially outside the subset.

5. A telephone subset comprising a base plate, a cover plate fitted to said base plate and provided with an aperture, a telephone signalling generator mounted on one of said plates beneath said cover plate, and means for driving said generator protruding from said aperture comprising a drive gear, means for rotating said gear, a gear train connecting said drive `gear and said generator, and a cover rotatable with said drive gear.

6. A telephone subset comprising an instrument supporting base plate, a cover plate tted to said base plate and provided with a circular aperture of such dimension as to accommodate the usual telephone dial, a telephone signalling generator mounted on said base plate beneath said cover plate, and means mounted on said base plate and protruding from said aperture for driving said generator comprising a ring gear, means for rotating said gear, a gear train connecting said ring gear and said generator, and a cover rotatable with said ring gear.

7. A telephone subset comprising an instrument supporting base plate, a casing having an aperture, a first bracket ixed to said base plate, a second bracket pivoted on said rst bracket and removably secured to said base plate, a telephone signal generator mounted on one side of said second bracket within said casing but spaced from said plate, another subset circuit component supported from said plate between said plate and said generator, and means mounted on the other side of said second bracket for operating said generator, said operating means extending through said aperture.

ERNEST S. MCLARN. 

